1. Technical Field
The invention relates to reroofing systems and methods of weatherproofing and sealing existing metal roofs and the fasteners which secure the metal panels to a roof deck. More particularly, the invention relates to such a reroofing system and method in which a highly flexible tape laminate having a pressure sensitive adhesive on one side covers the seams formed by adjacent panels and the fasteners to provide a weatherproof roof covering for metal roofs.
2. Background Information
Metal roofing systems for buildings usually consist of a plurality of metal panels which are overlapped at their ends and are secured to a roof deck or building structure by nails, screws, clips or other type fasteners. These metal roofs find applications in many building constructions, principally commercial and industrial buildings. However, the metal panels are subject to considerable movement together with the building, due to the expansion and contraction of the panels by heat, cold, wind etc., making it extremely difficult to provide a satisfactory weatherproof seal along the seams and at the fastener locations since over time the panels and their seams become loose.
Another common type of roofing construction is a single ply BUR (Built Up Roof System) which uses asphalt as an adhesive for attaching various types of membranes, such as felt or the like, to the metal roof panels. Although these systems are satisfactory for certain applications, the contraction and expansion of the roof panels often results in cracking of the roof covering along the seams and fastener locations, subjecting the roof to possible leakage. Also, these prior art roof constructions are relatively expensive to install and maintain and also increase the weight which must be supported by the roof surface. Also the use of hot asphalt may be prohibited by some local building codes. Therefor for many applications, such as for metal buildings, a roof of overlapping metal panels provide an inexpensive and satisfactory roofing system. However, these metal roofs are subject to the problems discussed above.
However, the reroofing of such metal roofs is required over time but is difficult since applications of other known roofing systems would require insulation layers or possibly a wood layer to accept the new roof. The relatively light gauge of the existing roof panels makes this additional layer difficult and expensive to apply effectively. Also the subsequent movement of the roof deck still causes cracks in the new roof.
Pressure sensitive adhesive tapes have been used in the roofing industry, primarily for adhering together flexible roof membrane or to adhere the flexible membrane to attaching devices. Also, such tapes have been applied to the roof flashing to provide a waterproof joint therebetween. Other types of sealing tapes and roofing attachments are shown in the following patents.
U.S. Pat. No. 4,732,635, discloses a method of making spliceable sheet material, wherein a transfer tape is applied to a sheet of uncured EPDM rubber membrane, and the assembly is subjected to heat and pressure to melt the adhesive and bond it to the membrane.
U.S. Pat. No. 4,601,935, discloses a roof seaming tape compound which contains butyl rubber and polyisobutylene. The tape is used to seal two EPDM membranes to each other along their respective adhesively-primed seams.
U.S. Pat. No. 3,654,005, discloses a thermoplastic sealing tape for window glass, which can be comprised of an EPDM rubber with a tackifier.
U.S. Pat. No. 4,437,283 discloses a roofing system of the batten type which uses sealing tape for securing the covering membrane to the roof and for sealing flanges of the end members with the roof sheet.
Japanese Patent No. 62-080027, discloses a tacky tape used to join two free adjacent ends of waterproof sheets in which the tape has a self-adhesive property and contains a butyl rubber.
However, none of these patents disclose the use of a tape laminate formed of butyl rubber and EPDM, in which the butyl rubber provides a pressure sensitive adhesive for securing the EPDM to the top surface of the butyl rubber and for securing the bottom surface to the metal panel seams and fastener locations to provide a weatherproof reroofing system for an existing metal roof.